Buy a ticket and join the fans at a game at Marguerite Aquatic Complex. If there's nothing scheduled while you're in town, you might like to check if there's a tour of the facilities.
You're spoiled for sightseeing choice when staying in Mission Viejo. Marguerite Aquatic Complex is a good place to kick off here, but there are loads of other fine spots to explore. Irvine Spectrum Center, Saddleback Church, and Saddleback College are near the sporting facility and will fill in your day nicely.
